Pivotal switch with rotor carrying two movable contacts and having three stable and one unstable operating positions

ABSTRACT

An electrical switch includes a body, and a rotor mounted for angular movement relative to the body. A first bridging contact is carried by the rotor, and first and second fixed electrical contacts are carried by the body, the first and second fixed electrical contacts being angularly spaced from one another and being bridged by the first bridging contact in a first angular position of the rotor. The switch further includes a second bridging contact movable in response to movement of the rotor to a further angular position to bridge the first and second fixed electrical contacts.

United States Patent Inventor Edward Cryer Iligham, near Burnley, England Appl. No. 17,056 Filed Mar. 6, I970 Patented Dec. 21, I971 Assignee Joseph Lucas (Industries) Limited Birmingham, England Priority Mar. 17, 1969 Great Britain 13,792/69 PIVOTAL SWITCH WITH ROTOR CARRYING TWO MOVABLE CONTACTS AND HAVING THREE STABLE AND ONE UNSTABLE OPERATING POSITIONS 3 Claims, 2 Drawing Figs.

U.S. Cl 200/6 R, 200/61.54, 200/166 BE, 200/166 J Int. Cl ..II0lh23/30, I-I0lh 21/ 1 8 Field of Search 200/166 [56] References Cited UNITED STATES PATENTS 2,418,616 4/1947 Batcheller ZOO/166 BE X 2,929,041 3/1960 Pettitt..... 200/153 K X 3,052,763 9/1962 Nathe.. 200/166 BE X 3,218,401 11/1965 Root 200/44 X 3,290,455 12/1966 Christensen 200/166 .1 X FOREIGN PATENTS 1,146,771 4/1963 Germany 200/44 Primary Examiner- Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Auorney-Holman & Stern 'PATENIEunEw l97l I 3.629.524

INVENTOR ATQRNEYS PIVOTAL SWITCH WITH ROTOR CARRYING TWO MOVABLE CONTACTS AND HAVING THREE STABLE AND ONE UNSTABLE OPERATING POSITIONS This invention relates to electrical switches.

A switch according to the invention includes a body, a rotor mounted for angular movement relative to the body, a first bridging contact carried by the rotor, first and second fixed electrical contacts carried by the body, and angularly spaced from one another said first and second electrical contacts being bridged by the first bridging contact in a first angular position of the rotor, and a second bridging contact movable in response to movement of the rotor to a further angular position to bridge said first and second contacts.

On example of the invention is illustrated in the accompanying drawings, wherein;

FIG. 1 is a sectional side elevational view of an electrical switch, and

FIG. 2 is a view in the direction of Arrow A in FIG. 1 with the lower part of the body of the switch removed.

Referring to the drawings, the switch includes a body 11 in the form of a pair of parallel, spaced insulating members 12,13 between which is positioned a moulded insulating rotor 14. The rotor 14 is journaled at 15 for angular movement between the members 12,13, in a plane parallel with the planes of the members 12,13. The rotor 14 includes an upwardly extending peg 16 which projects into an arcuate slot in the member 12, the length of the arcuate slot determining the angular distance through which the rotor 14 can move relative to the body 11. Extending from the rotor 14 at one side the axis of rotation of the member 14 is an operating lever 17, and on the side of the rotation axis of the rotor 14 remote from the lever 17, the rotor 14 includes a hollow, integral spigot 18.

Extending between the member 12 and the member 13, parallel to the rotational axis of the rotor 14, are four conducs tive posts 19,21,22 and 23. The posts 19,21,22 and 23 extend parallel to one another, and lie in an arc of a circle having its center on the rotational axis of the rotor 14. Each of the conductive posts 19,21,22 and 23 is extended at its lower end to define a terminal extending from the member 13 of the body 11. The spigot 18 of the rotor 14 carries a conductive ball 24 which is urged outwardly from the spigot 18 into engagement with adjacent pairs of the contacts 19,21,22 and 23 by a spring 25 within the spigot 18.

The rotor 14 is joumaled at 15 in the members 12,13 by means of a pair of coaxially oppositely directed posts integral with the rotor 14. Extending around the lower of the two posts is a conductive wire spring 26, the free end portions 27,28 of which extend towards the posts 19,21, 22,23. The portions 27,28 of the spring 26 cross one another intermediate their ends, and the free ends of the portions 27,28 are engaged with the conductive post 22, the resilience of the portions 27,28 of the spring 26 maintaining the free ends of the portions 27,28 in contact with the post 22. Extending downwardly from the rotor 14, towards the member 13 of the body 11 is a post 29 which, during angular movement of the rotor 14 relative to the body 1 1 can engage the portion 27 of the spring 26.

The posts 19,21,22 and 23, together with the spring-pressed ball 24 define three stable positions of the rotor 14 relative to the body 11. ln a first position, the ball 24 is engaged with the posts 22,23, and so completes a circuit therebetween. In the second and third stable positions of the rotor 14 the ball is engaged with the posts 22,21, and the posts 21,19 respectively, and so completes respective circuits therebetween. The rotor 14 is movable through the third position, to a fourth, unstable position wherein the ball 24 is engaged only with the contact 19. During movement of the rotor between the first, second and third positions, the spring 26 is stationary, and since the portions 27, 28 of the spring are engaged only with the contact 22, then the spring 26 does not complete any circuits within the switch. However, during movement of the rotor from its third to its fourth position, the post 29 engages the portion 27 of the spring 26 and as the rotor 14 achieves its fourth, unstable position, the portion 27 of the spring 26 is flexed out of engagement with the post 22 and into engagement with the post 21, thereby completing an electrical circuit between the posts 21,22. In order forthe circuit through the spring 26, between the posts 21 and 22 to be maintained, the rotor 14 must be held in its fourth unstable position. Upon release of the rotor 14 in the fourth position thereof the resilience of the portion 27 of the spring, together with the action of the spring returns the rotor to its third position.

In one practical embodiment of the switch, the switch is utilized to control the operation of a self-parking, two-speed, permanent magnet windscreen wiper motor. The post 22 is connected to an electrical supply, and so is the feed contact of the switch. The post 23 is connected in the fast speed circuit of the wiper motor, and the post 21 is connected in the slow speed circuit of the motor, so that in the first and second positions of the rotor 14 respectively, the ball 24 bridges the contacts 22,23 and the contacts 21,22 respectively, to complete the fast and slow speed circuits of the motor respectively. The post 19 is connected through one set of contacts in the parking switch of the motor, to earth, so that in the third position of the rotor, when the wipers associated with the windscreen wiper motor reach the end of a stroke, then the armature of the windscreen wiper motor is short-circuited to achieve dynamic braking of the motor. However, it will be appreciated that if the rotor is moved to its third position before the end of a complete stroke of the wipers, then the motor will continue to run until the wipers reach the end of their stroke.

By moving the rotor 14 to its fourth position, the slow speed circuit of the motor is completed through the spring 26. Thus, by momentarily moving the rotor to its fourth position, and then releasing the rotor so that it is returned to its third position, then the motor can be caused to operate to drive the wipers through one complete stroke.

It will be appreciated that the switch can be used to control a single-speed windscreen wiper motor in which case the post 23 is omitted from the switch. Where the switch is to be used for a single-speed motor, the range of angular movement of the rotor 14 relative to the body 11 need not be as great as that required when the switch is controlling a two-speed wiper motor. For this reason, the member 13 of the body 11 is provided with an arcuate slot of shorter arcuate length than the slot in the member 12 of the body 11, and the rotor 14 is provided with a second post 29a equivalent to the post 29, spaced from the post 29. Thus, a switch capable of controlling a singlespeed wiper motor can be constructed from parts common to a switch for controlling a two-speed wiper by assembling the switch with the rotor 14 together with the spring 26 inverted as compared with the switch described, and the post 23 is omitted. In such a switch, for controlling a single-speed wiper, the post 16 integral with the rotor 14 extends into the shorter slot in the member 13 of the body 11, and the post 29a engages the portion 27 of the spring 26 to move the portion 27 in a position of the rotor equivalent to the unstable fourth position in the switch for controlling a two-speed wiper.

Having thus described my invention what 1 claim as new and desire to secure by Letters Patent is:

1. An electrical switch including a body, a rotor mounted for angular movement relative to the body, a first bridging contact carried by the rotor, first and second fixed electrical contacts carried by the body and angularly spaced from one another, said first and second electrical contacts being bridged by the first bridging contact in a first angular position of the rotor, and a second bridging contact including a conductive spring having a pair of limbs both of which are urged by their own resilience into engagement with one of said first and second contacts, one of the limbs being flexed by the rotor into engagement with the other of said contacts, so that said second bridging contact bridges said first and second contacts, when the rotor is moved to a further position.

2. A switch as claimed in claim 1 including a further fixed electrical contact carried by the body, said first bridging contact bridging said further fixed contact and one of said first and second fixed contacts in a third angular position of the rotor.

3. A switch as claimed in claim 1 wherein said first bridging contact is a conductive, spring-operated bail, said springoperated ball further providing detent means retaining said rotor in the predetermined angular positions of the rotor.

t m m i m 5 

1. An electrical switch including a body, a rotor mounted for angular movement relative to the body, a first bridging contact carried by the rotor, first and second fixed electrical contacts carried by the body and angularly spaced from one another, said first and second electrical contacts being bridged by the first bridging contact in a first angular position of the rotor, and a second bridging contact including a conductive spring having a pair of limbs both of which are urged by their own resilience into engagement with one of said first and second contacts, one of the limbs being flexed by the rotor into engagement with the other of said contacts, so that said second bridging contact bridges said first and second contacts, when the rotor is moved to a further position.
 2. A switch as claimed in claim 1 including a further fixed electrical contact carried by the body, said first bridging contact bridging said further fixed contact and one of said first and second fixed contacts in a third angular position of the rotor.
 3. A switch as claimed in claim 1 wherein said first bridging contact is a conductive, spring-operated ball, said spring-operated ball further providing detent means retaining said rotor in the predetermined angular positions of the rotor. 